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Intracerebral calcifications are a facultative symptom of hypoparathyreoidism in 22q11.2 deletion syndrome (22qDS). We describe a patient with 22qDS, basal ganglia calcification (BGC) and psychotic symptoms and discuss the etiological connection of BGC with psychiatric symptoms. Future work needs to determine the prevalence of BGC in 22qDS and psychiatric disorders.
Durum wheat (Triticum durum) is predominantly grown as spring type and depending on the production area autumn or spring sowing is used. For the durum production in Austria and Germany, autumn sowing has several advantages, such as yield increase and stability, but this requires the selection for winter hardiness including a good frost tolerance. The aim of this study was to support breeding of winter durum and to facilitate genomic approaches by molecularly characterizing a panel of 170 diverse winter and 14 spring durum lines employing a genotyping-by-sequencing approach. We obtained an unprecedentedly high number of 30,611 polymorphic markers covering the entire genome. The principal coordinate analysis and the cluster analysis revealed the absence of a major population structure but a tendency of lines to group according to their country of origin. Linkage disequilibrium was found to decay within a short distance of approximately 2–5 cM and also showed variable patterns along chromosomes. In summary, our results can assist breeding of durum wheat and pave the way for genomic approaches towards knowledge-based winter durum breeding.
The spatio-temporal evolution of a turbulent swirling jet undergoing vortex breakdown has been investigated. Experiments suggest the existence of a self-excited global mode having a single dominant frequency. This oscillatory mode is shown to be absolutely unstable and leads to a rotating counter-winding helical structure that is located at the periphery of the recirculation zone. The resulting time-periodic 3D velocity field is predicted theoretically as being the most unstable mode determined by parabolized stability analysis employing the mean flow data from experiments. The 3D oscillatory flow is constructed from uncorrelated 2D snapshots of particle image velocimetry data, using proper orthogonal decomposition, a phase-averaging technique and an azimuthal symmetry associated with helical structures. Stability-derived modes and empirically derived modes correspond remarkably well, yielding prototypical coherent structures that dominate the investigated flow region. The proposed method of constructing 3D time-periodic velocity fields from uncorrelated 2D data is applicable to a large class of turbulent shear flows.
Las calcificaciones cerebrales son un síntoma facultativo de hipoparatiroidismo en el síndrome de eliminación 22q11.2 (22qDS). Describimos a una paciente con 22qDS, calcificación de los ganglios basales (CGB) y síntomas psicóticos y analizamos la conexión etiológica de la CGB con los síntomas psiquiátricos. Trabajos futuros tienen que determinar la prevalencia de la CGB en el 22qDS y los trastornos psiquiátricos.
Laser-crystallized polycrystalline silicon-germanium (poly-SiGe) thin films on glass substrates were characterized with energy dispersive X-ray and Raman spectroscopy. In the course of the crystallization strong lateral segregation occurs for laser-crystallized poly-Si1-xGex with 0.33 < x < 0.7, causing the local Ge content to differ by as much as 40 % from the average value. The segregation manifests itself in the appearance of well-resolved peaks in the Raman phonon modes. This mode splitting in the Raman spectra is interpreted as the formation of well defined alloy phases with a miscibility gap in between.
The preparation of μc-Si films from SiH4-H2 mixtures by electron-cyclotron resonance (ECR) CVD at deposition temperatures ≤ 400°C on foreign substrates is reported. Deposition conditions were identified for which Si films with a high degree of crystallinity were grown as was confirmed by Raman spectroscopy. A factorial analysis was carried out, for which the influence of deposition temperature, microwave power, hydrogen dilution and total pressure on film growth were investigated. Samples of optimized crystallinity were prepared in a lowpressure and high-hydrogen dilution regime. In-plane grain sizes were measured by TEM and found to be on the order of 10 - 12 nm. Next to the optimization of crystallinity several sources of impurity contamination during film deposition were identified and eliminated. Intrinsic μc-Si layers could be prepared under these conditions that exhibited a dark conductivity σd of 2 × 10-7 S/cm and photosensitivity σph/σd of 150. It is concluded that ECR CVD is capable of producing intrinsic layers with electronic properties as necessary for use in state-of-the-art n-i-p μc-Si solar cells.
A founder haplotype on chromosome 2p for autosomal dominant Parkinson's disease (PD) has
been postulated for two families of Northern European descent, and a new mutation in the
α-synuclein gene (Ala30Pro) has been found in a German PD family. We evaluated 85 German PD
patients and 85 ethnically matched controls for shared markers on chromosome 2p and for the new
α-synuclein mutation. We found no evidence for linkage disequilibrium, suggesting that the putative
founder mutation on chromosome 2p is not a common cause of PD in the local population.
Furthermore, no patient carried the Ala30Pro change, supporting earlier findings that mutations in
the α-synuclein gene are extremely rare.
Silicon films were grown on (100) n-Si with an electron-cyclotron resonance chemical vapor deposition (ECRCVD) system by decomposition of SiH4 at 325°C. Structure and composition of thin films were investigated by SEM, Raman spectroscopy, elastic recoil detection analysis (ERDA) and TEM. Excellent epitaxial growth was achieved for some hundred nm thickness. For more than 1 μm thick films, however, SEM revealed the occurrence of conical structures orientated upside-down with their basal plane in the film surface. Depth-profiling of the elemental composition of thin films by means of ERDA showed the hydrogen content CH to exhibit a pronounced increase with increasing film thickness. Raman spectroscopy evidenced the coexistence of c-Si and a-Si:H by the occurrence of two bands at 520 and 480 cm-1, the ratio of which was found to depend sensitively upon the position of the laser spot on the sample. All experimental results could be consistently explained by assuming the conical precipitates to consist of a-Si:H which was finally proven by coherent electron beam diffraction (CEBD).
Binary Zr-(Cu, Ni, Al) alloys were mechanically intermixed by cold-rolling stacks of elemental foils. The results indicate that solid-state amorphization is initiated if the grain size of the Zr-Cu and Zr-Ni alloys falls below a critical value. Amorphization was not observed for the Zr-Al alloy. These results are in accordance to the predictions of a model for solid-state amorphization. The comparison with the results on a quaternary Zr-Cu-Ni-Al alloy indicate the influence of multicomponent alloying on the glass-forming ability of Zr-rich alloys by mechanical working.
The microstructure evolution involving Mo-B-Si as-solidified alloys with compositions in the Mo solid-solution(ss) + T2 two-phase field has been examined following arc-melting and rapid solidification processing (RSP). Several solidification pathways in the arc-melted alloys have been identified. Compositional segregation during conventional solidification results in the formation of additional phases such as borides in the arc-melted alloys which require a prolonged solid-state annealing to obtain equilibrated two-phase microstructures. The RSP methods employed, splat-quenching (SQ) and powder drop tube processing (DTP), allow for significant microstructural modifications that facilitate the attainment of uniform dispersions of Mo(ss) phase in a T2 phase matrix.
Although the thickness of splat quenched (SQ) foils is normally less then 100 μm the solidified microstructure is usually not homogenous, but rather is determined by a cooling rate dependent nucleation and growth behavior of the different phases. The cooling rate and thus the microstructure changes significantly with distance from the edge to the middle of the SQ foils. Rapidly quenched nickel-vanadium (Ni-V) foils consist of three phases formed during solidification, a Ni-fcc, a V-bcc and a intermetallic σ phase [1-3]. To interpret the microstructure evolution in detail, a special TEM cross section sample preparation was applied. The SQ foil was ground to 30 μm, glued on a copper grid and ion-milled parallel to the foils (Fig.1a). In Ni-49V SQ foils seven typical microstructure regions (see Fig. 1 b) could be identified and were analyzed in detail by TEM investigations in plan view and cross section geometries. Furthermore, three solidification pathways were identified.
The reaction at the interface between Al and amorphous C in Al/C multilayer thin films with modulation wavelengths of about 25nm and 125nm has been investigated by differential scanning calorimetry, X-ray diffraction, transmission electron microscopy/selected area electron diffraction and high resolution transmission electron microscopy. The reaction was found to take place in two steps. The first step onsets at about 300°C, and was identified as the diffusion of C into Al. The second step starts above 400°C, at a temperature strongly dependent on the modulation wavelength of the film, and is the formation of A14C3. The carbide has been observed to nucleate and grow inside the Al layers. The multilayer structure is preserved in the samples up to at least 550°C, and Al grains start to grow at or below 300°C.
Multilayer samples of Nickel and Aluminum with an overall composition of Al-20Ni were prepared by cold rolling of elemental foils. The sample microstructures and phases were characterized by XRD, SEM and TEM/SAED, and the reactive phase formation was then examined by DSC measurements. XRD, SEM and TEM measurements show that the rolling procedure results in a decrease of the Al and Ni layer thicknesses (down to 100 nm in average) and a decrease of the grain size (down to less than 50 nm). No phase formation is observed during the cold rolling procedure. In isochronal DSC scans of the Al-Ni multilayers, the formation of the Al3Ni phase was found to be a two step reaction process due to 2-dimensional nucleation and lateral growth and a 3-dimensional phase thickening. While XRD measurements showed Al3Ni as the only phase that forms, more detailed TEM investigations of the samples after DSC treatment also showed a small amount of an amorphous Al-Ni phase, formed by a thermally activated solid state amorphization reaction (SSAR). In-situ TEM heating of the amorphous areas under the electron beam in the microscope yielded the crystallization of the amorphous phase to a B2 structure and a growth of the B2 grains up to 100 nm in size.
In multiphase materials systems involved in coatings, composites or multilayered structures, diffusion treatments often results in the development of intermediate phases at the reaction interfaces. While diffusional growth of phases has received much attention, the initial phase evolution involves a nucleation stage as well. The development of metastable phases during solid state interdiffusion demonstrates that the nucleation reaction can be controlling in some cases. For alloy systems with extensive solubility, intermediate phase nucleation is proceeded by interdiffusional mixing in order to achieve the required supersaturation. This leads to the identification of a critical concentration gradient for the onset of phase nucleation.The concentration gradient and the relative magnitudes of the component diffusivities provide a basis for a phase selection strategy and the application of a kinetic bias to modify the phase selection. For multicomponent alloy systems, the identification of the operative diffusion pathway is central to the control of phase formation. Experimental access to the nucleation stage of reaction is facilitated in thin film multilayer samples where the results from systems with both extensive and limited solubility offer new insight into the phase formation kinetics.
Elemental Zr-Al-Ni-Cu foils of bulk glass forming composition were cold rolled at ambient temperature. The phase transformations during the cold deformation process were monitored with electron and X-ray diffraction and thermal analysis. After 120 deformation cycles a fully amorphous sample was obtained, as indicated by a distinct endothermic glass transition and a large exothermic crystallization reaction. The characteristics of the amorphous phase are compared with a liquid quenched metallic glass and mechanically alloyed elemental powder mixtures of similar composition. The amorphization reaction during cold rolling is similar to mechanical alloying and proceeds by the formation of a fine layered structure of the constituents, a rapid reduction of the layer thickness and of the average grain size to a nanometer scale and dissolution reactions in the hcp Zr lattice. While in the beginning of the cold rolling process the elemental foils were ductile, after several rolling passes the multilayered sample became brittle and, finally, displayed large elastic flexure in the amorphous state. Several thermal treatments of the multilayered and amorphous samples were performed in order to study thermally activated solid-state amorphization reaction as well as phase formation during crystallization.
Epitaxial Mg-Fe-O spinel thin films were prepared by solid state reactions between MgO(lOO) substrates and thin films or vapors of iron oxide. Iron or iron oxide was deposited by electron beam evaporation in an oxygen background pressure onto a heated MgO crystal. The formation of MgFe2O4 at high temperatures proceeds via cation counter-diffusion in the fixed oxygen sublattice. Depending on substrate temperature, oxygen partial pressure and target material, epitaxial spinel films of different composition and magnetic properties were obtained. Crystal structure, composition and sub-micron morphology were investigated by RBS, XRD, TEM/SAED and EDX. Magnetic hysteresis loops were recorded at room temperature using the magneto-optic Kerr effect. Thickness interference fringes observed by XRD confirm the growth of smooth films. The main feature found in TEM plane view samples is a network of cation antiphase boundaries. The film composition measured by RBS varied from Fe2+ɛO3 films deposited at 340 °C substrate temperature to a solid solution of Fe2+E03 and MgFe2O4 at 500 °C to MgFe2O4 above 800 °C. EDX line-scans show a single phase MgFe2O4 spinel for a substrate temperature of 850 °C, without variation of composition with position or depth. At substrate temperatures higher than 800 °C Fe2+ was additionally dissolved in the MgO substrate, forming a FexMg1-xO solid solution.
Interfacial reaction mechanisms were investigated in case of topotaxial formation of MgIn2O4 spinel on MgO crystals, which is an appropriate model system for thin film solid state reactions in ceramics. The reaction interface MgO/MgIn2O4(001), which is characterized by a large lattice misfit (+4.2%) between these cubic crystals, was investigated by transmission electron microscopy (TEM). Thin spinel films (thickness t< 0.5μm) consist of domains tilted off (≈3.5°) the exact cube-to-cube orientation into four directions, while thicker films (t> 1μm) show an accurate (001) orientation. High-resolution electron microscopy (HREM) showed that this time-dependent orientation behavior correlates with the atomic scale structure of the interface, especially with the different types of misfit dislocations. Based on these results, the misfit accommodation mechanism at the propagating reaction front in this spinel system is discussed including transitions between glide and climb processes.
Microcrystalline silicon (μc-Si) films were prepared by electron cyclotron resonance assisted chemical vapor deposition (ECRCVD) using helium, argon and hydrogen dilution. The crystalline fraction was estimated from Raman backscattering spectra and scanning electron-microscopy (SEM) was used to obtain information on roughness and homogeneity of the films. For hydrogen dilution the highest crystallinity (Xc = 85 %) occurs at a ratio of ΔH = [H2]/([H2]+[SiH4])= 0.98. At the same time the deposition rate decreases continuously with increasing H2 dilution. These results are consistent with the idea that H etching promotes the growth of μc-Si. At ΔH > 0.98 a Xc decreases due to a H mediated transition of small crystallites into amorphous tissue. The implications of these results for the growth mechanisms are discussed.
Thin films of the orthorhombic perovskite GdAlO3 were grown on R-plane sapphire single crystals. Two different film growth methods were used, viz. (i) a chemical reaction of a Gd-O plasma with the sapphire crystals, and (ii) the reactive radio frequency (r.f.) sputtering of a GdAlO3 target. Subsequently, YBa2Cu3O7-δ (YBCO) films were deposited onto the GdAlO3 buffer by pulsed laser deposition (PLD). The GdAlO3 and YBCO films were investigated by Xray diffraction pole figure analysis and transmission electron microscopy (TEM), including highresolution transmission electron microscopy of cross sections. Independent of the deposition method the GdAlO3 films grew according to the nearly equivalent orientation relationships The GdAlO3 grains are additionally tilted by angles up to ± 3° around the sapphire [11.1] axis. On top of these buffer layers the YBCO films grew with c-orientation and with an in-plane rotation of 45°. YBCO films of 200 nm thickness on GdAlO3 buffer layers with a thickness of 10 to 20 nm showed a Tc > 87 K and a jc(77 K) > 3×106 A/cm2.